It is becoming increasingly common for mobile phones and related accessories (e.g. headsets) to include a broadcast FM radio receiver so that the user can listen to e.g. music stations. It is also becoming very common for mobile phones and accessories to include Bluetooth® wireless data transceivers. Since both technologies are reaching high market penetration, it becomes economically sensible to integrate both functions in a single integrated circuit.
When integrating some functions of a communication system in a single integrated circuit, the idea of sharing some components may arise. Such sharing of components is desirable since it reduces the total size and the cost of the integrated circuit. However, it is then not possible to operate e.g. both the FM receiver and the Bluetooth® transceiver simultaneously.
A typical operating condition for a Bluetooth® transceiver is to be in a “semi-idle” state where a link is maintained with its peers but little active transfer of data is performed. Such a situation is encountered when a link is established between a mobile phone and a Bluetooth® headset. In this situation, the duty cycle (on-to-off ratio) of the Bluetooth® device is low, with data transfer durations in the order of a millisecond. It is typically in such a state that a user may wish to listen to the FM audio broadcasts, e.g. in the Bluetooth®-enabled headset.